Crushing machinery



Feb. 2l, l939. s. sTEARNs v CRUSHING MACHINERY Filed Aug.v 27, 1935 /7 I9/ FFI ITT/250k? Patented Feb. 21', i939 UNITED STATES PATENT OFFICE CRUSHING MACHINERY Sheldon Stearns, Westfield, N. J. Application August 27, 1935, Serial No. 38,016

9 Claims. (Cl. 83-10) My invention relates to improvements in crushing machinery, in particular to the type of crushing machinery known as gyratory crushers.

/ In a gyratory crusherthere is usually a cenr, trally located conical crushing or breaking head mounted upon a vertical shaft. One end of this vertical shaft'is gyrated by means of an eccentric driven directly or indirectly by a motor. 'Ihe other end of the shaft is centrally and pivotally 10 mounted. Surrounding this conically shaped head are stationary concaves or crushing surfaces so shaped as to form a large entrance opening between the conical head and the concaves at the top, and a continuously narrowing space bei5 tween the head and the concaves towards the lower or discharge end. The shaft and head do not revolve, but are so gyrated that the head moves towards and away'from the concaves at every point of its circumference, once for every revolution of the eccentric. The minimum clearance between the heads and the "concaveat the discharge end is set to produce a crushed material to some definite and desired size'or fineness. Material to be crushed is introduced at the top or entrance opening between the head and concaves, and as it is gradually crushed to size, due to the' gyrating motion of the head, it drops and is finally discharged from the lower or discharge end of the crusher.

In practice I have found that frequently packing or. choking of the material to be crushed occurs as` the material approaches the smaller clearances between the gyrating head and the .conn

caves ator near the discharge end of the crushers. This packing of terial -produces heavy stresses pack, compress still further and permit the concaves to move vertically upward and increase thel clearance between them and the gyrating head. Another vmethod used for relieving the pressure of high stresses is to have the concaves held staU4 tionary and to permit the shaft carrying the gyrating headzto move vertically downward so as to increase the clearances between the concaves and the head. When such automatic ad- 55 Vjustments of either the concaves or head occur,

as occur.I when the crushing material begins to the material crushed is no longer of uniform fineness,but is coarser due to the increase of minimum clearance. By resorting to the above means of relieving thepressures, which are caused by packing of the material between the crushing surfaces, ineiiiciency of crushing results4 on ac-` count of the cushioning effect due to the use of springs supporting the main crusher shaft, or springs so arranged to allow the frame supporting the concaves to move vertically upward. This necessarily increases the power required to drive the crusher. However, in spite of the precautionstaken to automatically relieve the crusher of the high stresses due to packing or choking, important parts of the crusher wear rapidly requiring expensive renewals, and parts frequently fail.

My invention consists in so designing and constructing the gyrating head and concaves that the crushing is performed in certain definite stages or steps.

The first crushing stage serves to crush the n material from its original size to some definite intermediate size. It is then discharged from the rst crushing stage and allowed to enter a second crushing stage. Two or more stages are used for crushing the material from its original size to the desired ilner'size. The crushing stages are so arranged that the material in passing from any crushing stage is received in a succeeding stage having a considerably greater crushing surface than that of the preceding crushing stage.

The discharge space between the concaves and the crushing heads of the first stage is so designed that it does not pass more material at that point than can be accommodated or crushed during an equal interval of time in the second crushing stage. If the crushing of a material is accomplished in more than two stages,` the discharge space of each crushing stage isso proportioned that it does not pass more' material than canbe crushed in an equal interval of time in the succeeding stage.

In other words, in the presentA type of gyratory crusher, especially when, making large. reductions in the sizes of the materialy to be crushed, there is no control of the flow of material from the time it enters the receiving opening of the crusher until it reaches the discharge end of the crusher. Whereas in the crusher of my invention, in which the crushing is performed in stages, I have controlled crushing by so proportioning the discharge 'opening of each stage that it cannot discharge more material than caribe accommodated in the succeeding stage,4 thus obviating entirely any choking or packing of the crushed material so frequently occurring in the present types of fine reduction Crushers.

'I'he present types of gyratory crushers may be classified as either coarse crushers, medium crushers, or ilne reduction crushers. When it is desired to crush coarse material to a fine size,

two or three separate crushers are sometimes employed, the final fine crushing can also be done ingrinding machinery such as ball mill's or rolls.

Crushers according to my invention can crush in a single unit, a coarse material to a fine material, where heretofore such reductions had to be made in more than one crushing unit. By crushing the material in stages I virtually control the flow of the material at certain definite points throughout the crushing operation. The amount of material flowing from one crushing stage to another is entirely controlled by the discharge opening between the head and concaves of each stage. The proper choice of such control points depends upon the kind of material to be crushed,

as for instance, its hardness or friability. Should the amount of material passing from one crushing stage to another be greater than the latter stage can accommodate without choking or packing, it is only necessary to reduce the discharge opening of the previous stage by adjusting orinclining the head or the concaves to such an extent that the previous stage will not discharge more material than the succeeding stage can crush and discharge without packing.

,Another important advantage in crushing material in definite stages is the ease in which the crushing areas or surfaces can be greatly increased in' any given stage over that of the preceding stage. For a given quantity of material much greater crushing areas or surfaces are necessary as the material approaches its reduced size than when it is in a coarse form.

For example, in the present type of gyratory Crushers having a diameter at discharge end of say three feet, eighty tons of a certain material can be crushed per hour to one inch size. If this same crusher is to crush the same material to one-half inch size by readjusting the discharge opening, only forty tons of material per hour can be crushed, and if the discharge opening is set to produce a material of one-quarter inch size, the capacity of the crusher drops to twenty-five tons per hour. Therefore it can be seen that although the upper part of the crushing surfaces of this gyratory crusher is capable of handling eighty tons of material per hour, the intermediate and lower crushing zones of the crusher are only capable of handling a much smaller quantity of material per hour. This means that the crusher can deliver more material to the intermediate and discharge zone than can be handled by them, and as a result under these conditions, the material frequently chokes or packs towards the discharge end of the crusher causing undue strains and excessive power consumption.

However, in the crusher of my invention, if the rst crushing stage is made to'crush eighty tons of material per hour to one inch size, the head and concaves being made about three feet in diameter at the discharge end, and if the second stage is to crush this material to one-half inch size, the head and concaves are made about four feet in diameter. If this same material is to be crushed to one-quarter inch size, a third crushing stage. is used having a diameter of head and concaves considerably larger than the previous stage so as to have a capacity sufcient to take care of the original quantity of material passing through the preceding stages of the crusher.

The above data is given only as an illustration, but in the actual designing of a multi-stage crusher according to my invention, reductions made in each stage andthe various diameters necessary for the head and concaves must be determined by the designer to suit the actual requirements.

Another advantage of my invention lies in the fact that if the crushing is performed in definite stages each lstage can be designed with nearly vertical crushing surfaces. It can readily be understood'that the more nearly vertical the crushing surfaces are, the more readily will the material pass through the crusher by gravity. In the present types of gyratory Crushers the desire to greatly enlarge the area of crushing towards the discharge end resulted in inclining the crushing surfaces at a considerable angle from the vertical, which retards the gravity flow of the material, and if inclined too much causes pack- 111g.

A further advantage of my invention vlies in the fact that if the crushing is performed in definite stages in which each stage does not discharge more material than can be accommodated in the succeeding stage, thus eliminating choking and packing, the power required for crushing is reduced to a minimum.

For a more detailed understanding of my invention reference is to be made to the following description and the accompanying drawing of practical embodiment of the inventive idea, and. vin which drawing the figure is a part sectional view of a gyratory crusher showing. particularly the gyratory head and concaves.

Referring to the figure the electric motor for driving the crusher is shown at I. This motor drives the vertical shaft 2 through the coupling 3. The lower end of the vertical shaft 2 is keyed and fastened to an eccentric bushing 4. The outer surface of the eccentric bushing is journalled in a stationary frame 5, and the inner surface of the leccentric bushing rotates about the hollow gyrating shaft 6. This hollow gyrating shaft permits the driving shaft 2 to pass through it without contact and carries the crushing heads 'I, 8 and 9 on its enlarged tapered portion. The

gyrating shaft 6 near its upper end is centered and pivotally mounted in a ball seated bearing |0, and is supported at its threaded upper portion by the nui'l II. The motor I in turning the shaft 2 rotates the eccentric 4, which in turn oscillates the gyrating shaft G about its upper and centrally located pivot I0. The weight of the motor and all the rotating and gyrating parts is carried by the spider casting I2 mounted upon the stationary frame I3. This frame is suspended by a number of suspension wire ropes I4 from a fixed support above the Crushers and not shown in the figure. Surrounding the crushing heads "I, 8 and 9 are stationary concaves I5, I6 and I1. These concaves are arcuate in form and when properly mounted in the supporting frame I3, a number of them will form a complete circular stationary crushing surface around each of the gyrating heads 'I, 8 and 9. 'I'he usual number of concaves to a complete circular set consists of from five to fourteen separate castings, depending upon the size of the crusher, but when conditions concaves, including ring concaves, can be backed with zinc asis usual in all types of gyratory crushers.

As shown inthe figure the space between the crushing headsI and their .corresponding concaves is larger at the top than at the bottom or discharge end. Material is introduced into the -space at the top between the crushing head 1 titi and the concaves I and is crushed to the size of the minimum clearance between the head and the concaves at the discharge end. The material is then guided by the sloping surfaces, i8 of the crushing head and I9 of the frame into heenlarged receiving opening of the next crushing stage, that is, into the upper part of the space between the head 8 and the concaves i6. In the space between the crushinghead 8 and concaves I6 thel second stage of crushing is performed. The minimum clearance at the bottom of this space is less than the minimum clearance in the first crushing stage. discharged from the second crushing stage is again guided by the sloping ysurface of the4 gyrating headand the sloping surface 2i of the frame to the entrance of the third crushing stage, that is the space between the crushing head Si and concaves I1. `Therninifrnum discharge opening between the third crushing head 9 and the third setof concaves l1 is made so as to deliver thev crushed material of the desired size or fineness. Obviously, therefore, to provide in a crusher according to my invention, a structure wherein each stage can not discharge more material than can be handled by the nextsucceeeding stage, the discharge openings ofall of the crushing stages must have approximately equal active discharge areas.

The material upon beingdischarged from the lastcrushng stage drops upon the inclined surface 22 of the frame and is discharged through a sui-table opening 2t of the frame of the crusher. drawing, the inclined guiding or conveying sur-4` faces it and 2U are formed on thegyrating crushing head' and move therewith, for shaking the material as it passes from one stage to @the succeeding stage, thereby aiding gravity action in distributing the lmaterial into the inlet ofthe succeeding crushing stages. Also as clearly shown in the drawing, these conveying surfaces I8 and 2U are inclined at much smaller angles to the horizontal than are the inclined surfaces of the crushing heads 1, 8 and 9.

.The crushing surfaces'bothof the head and ofthe concaves are made of a'hard and wearresisting material, such as manganese steel. The crushing heads shown in the figure consist of cast iron or castl steel head centersmounted onl the main gyrating shaft and having manganese steel zinced mantles mounted` on the head centers and held in position with the necessary locking devices. If the crusher shown in the iigure is used for crushing ing stage to the succeeding crushing stage I8, I9, 20 and 2l lshould be made of wear-resisting material.

The proper choice of minimum crushing openings of all the crushing stages preceding the last crushing stage depends largely 'upon the kind of material to be crushed and also whether'the material is crushed wet or dry.

Stage crushing, according to my invention, permits theintroduction of water into any of the later stages of the crushing operation, when it is vfound desirable to do so. This cannot .be done in The material after being As clearly shown in the` hard and .abrasive ma- 'teriaL the conducting surfaces from one 'crusha. practical manner .in the present type of gyratory crusher, especially in a fine reduction crusher. f

1t will be noted that niecrshing heads of each stage in the figure extend slightly below the bottom-Nif the corresponding concaves. `This is the usual practice so as to permit compensating for wear of the crushing surfaces by slightly raising the entire crushing head. Should, however, too much material be discharged from any crushing stage into the succeeding crushing stage so that the'latter cannot take care of the material in its stage, it is only necessary to decrease the minimum clearance of the precedingstage so that less material will pass that point, and by this means obviate the choking or packing of the material in the succeeding stage. vlDecreasing the minimum clearance in any one vcrushing stage mantle to accomplish the same results. In any crushing stage the larger part of the wear usually takes place at the discharge end. lin a crusher of my invention it is possible to so design the crushing surfaces of the segmental concaves or ring concaves of any'stage so that they may be reversed in such a mannerthat the worn surface of the discharge end is placed at the'top and the less worn surfaces of the top -are now placed at the bottom, thus allowing double wear of the crushing surfaces of the concaves, and obviating too frequent renewals of the concaves.

As has been mentioned before, any material to be crushed requires more crushing surface or area as the material is vreduced to a smaller size because the voids are greatly reduced. In the figure, it should be noted-the ease with which the crushing surfaces or crushing areas can be greatly and quickly increased from stage to stage and still retain the Vcrushing surfaces in each crushing stage in a nearly vertical position. This permits the material being crushed to drop more rapidly between the crushing surfaces.

Referring to the figure, I obtain control crushing Iby being able to adjust the discharge opening of each crushing stage. If too much material flows from one stage to another, the discharge opening of the former crushing stage in question is made smaller, and if less material is discharged from the stage than can be accommodated in a succeeding stage, the discharge opening of the previous stage can be increased so as to permit a greater flow of material.

I have called attention to the fact that my invention necessitates all crushing stages to crush the same quantity of material in equal intervals of time. This requires making the discharge areas of all stages such that they will permit the same weight of material to pass through them in an equal interval of time. For example, let us consider two-stage crushing in a gyratory crusher vin which the first stage is to have a minimum discharge opening between head and concaves of 1k inch, and that the diameter of the gyrating head at the' discharge point is 33 inches. Taking the. eccentricity ofthe gyrating head at this point to .be 1A inchQthe diameter of the opening of theconcaves at the discharge point will then be I34%; inches. The area ofthehead at this point is 855.3 sq. in., ancNzhe area of the opening of the concave at this point is 921.3 sq. in., the dif ference of these two areas, 66 sq. in., is the area of the discharge opening of the first stage. This discharge area will pass a certain weight of crushed material. At any instance, only a part of the discharge area extending around part of the circumference of the head is discharging crushed material, while the remaining area is discharging very little material because crushing of the material is taking place. Suppose it is found' that '70% of the discharge area is actually discharging crushed material at any instance, then 70% of 66 sq. in.I gives 46.2 sq. in. active discharge area.

Corrections of discharge area must also be made to take into account the percentage of voids existing in the crushed material; and also corrections must be made taking into account the number of gyrations of the head per second, because each gyration of the head stops and then permits again the movement of material through the discharge opening by gravity, thus limiting the free gravity flow of the material. Corrections also must be made as to the influence ofthe inclination from the vertical of the crushing surface of the head, as its frictional resistance to the material interferes with the acceleration of the material due to gravity.

Suppose all of these corrections reduce the Weight of material discharged to that which would be discharged continuously by an equivalent opening of 40 sq. in.

Now let us s uppose the second stage is to have a minimum discharge opening of T56 inch, and that the eccentricity of the gyrating head at the discharge of this second stage is inch. 'If the diameter of the second stage gyrating head at the discharge is 46 inches, then the diameter of the concaves at this point will be 47 inches. The area of the headat 46 inches diameter is 1662 sq. in. and the area of the opening of the 4'7" diameter concave is 1735 sq. in., then the discharge area is 73 sq. in. If 60% of, this area is actually discharging material at any instance, then of 73 sq. in. gives 43.8 sq. in. as the active discharge area.

Suppose all the other corrections mentioned above, reduce the weight of material discharged to that which Would be discharged continuously by an equivalent opening of 40 sq. in., then thel second stage of this crusher will discharge the same quantity or Weight of material as is discharged by the first stage.

vIt is, of course, obvious that although three stage crushing is shown in the drawing, those skilled in the art can apply my invention to only two stage crushing or to multiple stage. crushing, having more than three stages. It is also obvious that those skilled in the art can apply my invention to various other types of crushing machinery.

In the crusher of my invention it may also be desirable to have a number'of peep or hand holes located ninety degrees apart below the bottom of the concaves of each stage. These are not shown on the drawing. They are to be used for inspecting and determining -the opening between head and concaves at the discharge end of each crushing stage.

In a crusher according to my invention it may be found desirable to crush the material dry in the early crushing stages and wet in the succeeding crushing stages, and if so, water can be easily introduced at several points around the circumference of the entrance to the crushing stage in which water is to be introduced.

It is to be understood that in a crusher built according to my invention, the shape or profile of the crushing surfaces, the depth of the crushing surfaces of each stage, the angle between the crushing surfaces of the head and concaves of eachstage, and the diameters of head and concaves of each stage may all be varied to suit the particular material that is to be. crushed.

Also, the slope of the guiding surfaces which convey the material from the discharge of one crushing stage into the opening of the succeeding stage may be varied to suit the particular material to be crushed and whether the material is crushed wet or dry.

In the preceding subject matter and in the appended claims the expressions equal active discharge area and discharging an equal weight of material in an equal interval of time" have been used in connection with theproper design of the various stages of the crusher. In the pren ceding subject matter the expression equal active discharge area has been explained and illustrated and as there explained this expression does not mean that the physical discharge openings of the various stages are of equal area. The expression discharging an equal weight of material in an equal interval of time is used to describe a feature of construction of the crusher of the present application which is not found in prior Crushers. of a multi-stage crusher designed according to this invention is to have a capacity of 100 tons of material per hour crushing material say from 5 size to 2" size when this rst stage is crushing material alone as a single stage crushen Suppose now a second stage is added to crush the material from 2" size to 3A size. It should That is suppose the rst stage have a capacity of 100 tons per hour when this second stage operates entirely independently. Let us suppose that a third stage is added to crush the material from 1% size to 1A size. It should therefore also have a capacity of 100 tons per hour when it would be operating alone and in- 80 tons an hour it would choke back the rst stage so that it too would only deliver 80 tons an hour and if the third stage is added with a capacity of only 60 tons an hour it would choke back the material of the second stage to 60 tons an hour and the second stage would then permit only a discharge of 60 tons an hour from the first stage.

However, in the latter case although all threestages are discharging 60 tons an hour in equal intervals of time the stages previous to the third stage are not operating at their full capacity. The rst examplein which all 1three stages operate at their full capacity and discharge 100 tons of material an hour is considered the proper proportioning of all three stages according to the present invention and the second case where the crusher capacity was only 60 tons an hour due to the limitations existing in the third stage of the crusher should be considered an improper proportioning of the crusher according to my invention. Or in a two-stage crusher where the first stage has an individual capacity of 100 tons an hou'r and in the second stage of only 80 tons an hour is also an improper proportioning of a multi-stage crusher according to my invensmall a capacity of asucceeding stage.

lil

tion. Hence the term discharging an equal weight of material in an equal intervalof time refers to the full capacity of each stage of the crusher when there is no choking and decreasing the'capacity of a previous stage due to too The present invention therefore consists in arranging, proportioning and constructing all the stages of a multi-stage crusher so that each stage has thesame capacity of any of the other 'stages when they are operating independently of each other. The present invention also consists in theV provision of conveying surfaces between stages which will deliver the material from one stage to the succeeding stage` in such manner as to facilitate the effective continuous operation of the entire machine and deliver the material from lthe smaller diameter crushing headto the successive larger diameters of the crushing heads. c

In accordance with the provisions ofthe patent statutes, I have described the principle of operation of my invention together with the apparatus which I now consider to represent the best embodiments thereof but I desire to have.

itunderstood that the apparatus shown is only illustrative, and that the invention can be carried out by other means.

What I claim as new and desire to secure by Letters Patent of the United States, is:

l. A gyratory Crusher having two or more Crusher heads mounted on a gyrating shaft and having each crusher head surrounded by a suitable stationary concave so arranged and constructed that eachY crusher head together with l its corresponding concave form a definite crushing stage so that the material to be crushed passes successively from one crushing stage to another where it is consecutively crushed to a finer size, and having each successive crushing stage so designed and constructed that it has its entire crushing surfaces at substantially greater diameters than those of the preceding stage, and having movable non-crushing means for conveying the material to be crushed from one stage of small diameter to the succeeding stage of materially larger diameter. l

2,. A .gyratory crusher having two or more crushing heads of progressively and substantially larger diameters, mounted on a gyrating shaft,. each crusher -head surrounded by suitable sta-v tionary concaves so as to. form definite crushing'stages, and having every part of the crushing surfaces of each crushing stage of a larger diameter than any part of the crushing surfaces oi. the preceding stage, and so designed and constructed that thematerial to be crushed passes through the crushing stages in sequence from the smallest diameter stage to the next larger. one, and having the activedischarge areas of all stages substantially equal.v y

3'. A gyratory crusher having crushing surfaces mounted on a gyrating shaft and having station-- ary, crushing surfaces surrounding them and so designed and constructed thatthe material to be crushed passes between the gyrating-A and stationary crushing surfaces. in an approximately vertical direction, and in which the crushing is performed in successive stages having greatly increased diameters and also greatly increased crushing areas than those ofthe preceding stage,

I and having the discharge areas of all the stages so proportioned that equal weights of material pass through them in equal intervals of time, and movable means for conveying the material to be crushed from the discharge opening of one 4. A gyratory rusher having two or. more heads.

mounted on a common gyrating shaft, each head surrounded by stationary concaves andV so -designed and constructed as to forml definite crushing stages, each succeeding stage being of a considerably greater diameter than that of the preceding stage, and inclined conveying surfaces between each crushing stage for conveying material to be crushed from one stage to another.

5. A gyratory crusher embodying a plurality of gyrating crushing surfaces to crush material in successive stages and having the discharge opening of each stage of less diameter and greater width than those of the discharge opening of the succeeding stage, and said gyrating crushing surfaces being of such size and proportions with respect to said discharge openings that 'all ofthe discharge openings will always have approximately active equal discharge areas, and inclined non-crushing conveying surfaces between Vsaid stages for conveyingmaterial from one stage to the succeeding stage. y

6. Ina gyratory crusher, a series of concaves, gyrating crushing means cooperating with said concaves and including a plurality of crushing heads having their crushing surfaces inclined with respect to the vertical axes, said crushing means including conveying surfaces betweenr said crushing heads, said conveying surfaces inclined at angles to their vertical axes greater Vthan the angles of inclination of said crushing surfaces.

7. In a gyratory crusher, a movable crushingr member comprising alternate crushing and conveying surfaces, said crushing surfaces being arranged to crush material in successive stages, the crushing surface of each stage. being of predetermined proportional greater diameter than that of the crushing surface of the preceding'stage, said crushing surfaces being inclined, said conveying vsurfaces being inclined at relatively atter degrees of inclination with respect to the horizontal than the,degrees of inclination of the crushing surface.

8. lin agyratory crusher, a frame, a plurality of concaves carried by said frame, a plurality of with said concaves to crush material in successive stages and form with said concavesv discharge openings for each stage, a motor for driving said crushing heads, conveying surfaces between said heads and spaced from the frame a distance discharge opening whereby the conveying surfaces will be noncrushing, said crushing surfaces being inclined, said conveying surfaces being in` clined` at relatively flatter degrees of inclination vmovable crushing heads arranged to co-uperate..`

greater than the 4maximum width of the adjacent with respect to the horizontal than the degrees of rial to or smaller than a predetermined denite size in a definite interval of time, the crushing surfaces of each successive stage being of larger diameter than .the crushingl surfaces of the preceding stage and proportioned and arranged with respect to each other and to the crushing surfaces of the preceding stage so as to crush at least the degrees of inclination of the crushing surfaces whereby the material being crushed will be caused to make an abrupt turn in its direction of travel in passing from one crushing stage to the succeeding stagefor causing a spreading of the material over 5 the gyrating conveyingl surface.

SHELDON STEARNS. 

